In the early days of the automobile the exterior finish was relatively primitive both in method of application and formulation. When first introduced, the Ford Model T was hand painted using a rake-like device which poured on flowing paint, the excess of which was captured in a tub for re-use. The paint itself was a solvent-based varnish. While available in such colors as blue and green these colors appeared to be virtually black unless viewed in bright sunlight due to the varnish paint. This characteristic contributed to the mistaken belief that all Model T's were black.
As with all other areas of automotive technology painting techniques and paint composition have developed dramatically since those early days. Today's paints, including environmentally-friendly powder coatings which are based on acrylic binder chemistry and thus contain no solvents, are applied in far more sophisticated ways to achieve more durable and appealing results. Today's paints include aluminum flakes, micas, and other particulates to create desired pigmentation. These paints are highly durable and resist fading even when exposed to the harshest environment.
Despite significant advances in knowledge of the composition and characteristics of automotive paint, as new and more complex exterior paint colors are introduced to the automotive industry, unique challenges remain in controlling the quality and accuracy of the application of these colors. While the use of new pigments is one method of creating new colors, another is through the creation of multiple color layers in the paint system, giving rise to a unique appearance. These color systems include, but are not limited to two-tones, tri-coats, and tinted clearcoat systems. With these new technologies come unique challenges in controlling the quality of the paint colors, insuring that not only are the correct color layers applied, but that they are applied correctly over the entire vehicle.
In some cases, an error in the color application is not obvious to the casual observer, and the defective vehicle will make it through final assembly before the defect is identified. To correct the error, a paint repair is done to the unit in order to make it acceptable for delivery. This repair is costly in terms of time, labor and material.
Accordingly, a simple, automated system is needed to monitor the paint color across critical color regions on the vehicle and to identify when gross color mismatches occur while allowing for the acceptable part-to-part color shifts that occur in production throughout the day.